Regenerative braking system and method using air conditioning system of electric vehicle

• US 20050007049A1
• Filed: 12/16/2003
• Published: 01/13/2005
• Est. Priority Date: 07/07/2003
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Kim, Tae Woo
• Granted Patent: US 6,989,644 B2
• Time in Patent Office: Days
• US Class Current: 318/376
• CPC Class Codes: B60L 1/02 to electric heating circuits
• CPC Class Codes: B60L 1/04 fed by the power supply line
• CPC Class Codes: B60L 7/06 for vehicles propelled by ac motors
• CPC Class Codes: H02M 7/5387 in a bridge configuration

Abstract

The regenerative braking method and system for an electric vehicle in which regeneration current is calculated and controlled using control of an air conditioning system to consume a portion or all of the surplus regeneration power, thereby enhanding braking performance and feel.

Claims

1. A regenerative braking method for an electric vehicle, comprising:

determining whether a brake of the electric vehicle is operating;

calculating a regeneration current based on a brake operation value if it is determined that the brake is operating;

determining whether the regeneration current is greater than a battery current limit;

calculating a surplus regeneration power if it is determined that the regeneration current is greater than the battery current limit; and

controlling an air conditioning system to consume a portion or all of the surplus regeneration power.

2. The regenerative braking method of claim 1, wherein the calculating a surplus regeneration power comprises:

calculating a surplus regeneration current by subtracting the battery current limit from the regeneration current; and

calculating the surplus regeneration power by multiplying the surplus regeneration current by a battery voltage.

3. The regenerative braking method of claim 1, wherein the controlling the air conditioning system comprises:

calculating consumable power of an air heating device of the air conditioning system that can be currently consumed by the air heating device;

determining whether the surplus regeneration power is less than the calculated consumable power of the air heating device; and

controlling the air heating device to consume all of the surplus regeneration power, if it is determined that the surplus regeneration power is less than the consumable power of the air heating device.

4. The regenerative braking method of claim 3, wherein the consumable power of an air heating device is calculated based on a current duty of the air heating device and a rated power of the air heating device.

5. The regenerative braking method of claim 4, wherein the consumable power of the air heating device is calculated by multiplying a difference between a maximum duty and the current duty of the air heating device by the rated power of the air heating device.

6. The regenerative braking method of claim 3, wherein the controlling the air heating device comprises:

determining a duty of the air heating device as a duty in which all of the surplus regeneration power can be consumed by the air heating device; and

outputting a driving signal corresponding to the determined duty of the air heating device to the air heating device.

7. The regenerative braking method of claim 6, wherein the duty of the air heating device is determined by summing a current duty of the air heating device and a duty for the air heating device to consume the surplus regeneration power.

8. The regenerative braking method of claim 3, wherein the controlling the air conditioning system further comprises determining a duty of the air heating device as a maximum duty, if it is determined that the surplus regeneration power is not less than the calculated consumable power of the air heating device.

9. The regenerative braking method of claim 3, wherein the controlling the air conditioning system further comprises:

calculating an amount of power that can be currently consumed by the air cooling device, after determining the duty of the air heating device as the maximum duty;

determining whether a remaining portion of the surplus regeneration power that has not been consumed by the air heating device is less than the calculated consumable power of the air cooling device; and

controlling the air cooling device to consume all of the remaining portion of the surplus regeneration power, if it is determined that the remaining portion of the surplus regeneration power is less than the consumable power of the air cooling device.

10. The regenerative braking method of claim 9, wherein the consumable power of the air cooling device is calculated based on a current duty of the air cooling device and a rated power of the air cooling device.

11. The regenerative braking method of claim 10, wherein the consumable power of the air cooling device is calculated by multiplying a difference between a maximum duty and the current duty of the air cooling device by the rated power of the air cooling device.

12. The regenerative braking method of claim 9, wherein the controlling the air cooling device comprises:

determining a duty of the air cooling device as a duty in which all of the remaining portion of the surplus regeneration power can be consumed by the air cooling device; and

outputting a driving signal corresponding to the determined duty of the air heating device to the air cooling device.

13. The regenerative braking method of claim 12, wherein the duty of the air cooling device is determined by summing a current duty of the air cooling device and a duty for the air cooling device to consume the remaining portion of the surplus regeneration power.

14. The regenerative braking method of claim 9, wherein the controlling the air conditioning system further comprises determining a duty of the air cooling device as a maximum duty, if it is determined that the remaining portion of the surplus regeneration power is not less that the calculated consumable power of the air cooling device.

15. A regenerative braking system for an electric vehicle comprising:

a motor capable of generating a regeneration energy while the electric vehicle is being braked;

an inverter converting the regeneration energy generated by the motor to a regeneration current;

a battery configured to be charged by the regeneration current;

an air conditioning system that is operated by a current of the battery or the regeneration current; and

a control unit controlling an operation of the air conditioning system, wherein the control unit is programmed to perform;

determining whether a brake of the electric vehicle is operating;

calculating a regeneration current based on a brake operation value if it is determined that the brake is operating;

determining whether the regeneration current is greater than a battery current limit;

calculating a surplus regeneration power if it is determined that the regeneration current is greater than the battery current limit; and

controlling an air conditioning system to consume a portion or all of the surplus regeneration power.

16. The regenerative braking system of claim 15, wherein the calculating a surplus regeneration power comprises:

calculating a surplus regeneration current by subtracting the battery current limit from the regeneration current; and

calculating the surplus regeneration power by multiplying the surplus regeneration current by a battery voltage.

17. The regenerative braking system of claim 15, wherein the controlling the air conditioning system comprises:

calculating an amount of power of an air heating device of the air conditioning system that can be currently consumed by the air heating device;

determining whether the surplus regeneration power is less than the calculated consumable power of the air heating device; and

controlling the air heating device to consume all of the surplus regeneration power, if it is determined that the surplus regeneration power is less than the consumable power of the air heating device.

18. The regenerative braking system of claim 17, wherein the amount of consumable power of an air heating device is calculated based on a current duty of the air heating device and a rated power of the air heating device.

19. The regenerative braking system of claim 18, wherein the consumable power of the air heating device is calculated by multiplying a difference between a maximum duty and the current duty of the air heating device by the rated power of the air heating device.

20. The regenerative braking system of claim 17, wherein the controlling the air heating device comprises:

determining a duty of the air heating device as a duty in which all of the surplus regeneration power can be consumed by the air heating device; and

outputting a driving signal corresponding to the determined duty of the air heating device to the air heating device.

21. The regenerative braking system of claim 20, wherein the duty of the air heating device is determined by summing a current duty of the air heating device and a duty for the air heating device to consume the surplus regeneration power.

22. The regenerative braking system of claim 17, wherein the controlling the air conditioning system further comprises determining a duty of the air heating device as a maximum duty, if it is determined that the surplus regeneration power is not less than the calculated consumable power of the air heating device.

23. The regenerative braking system of claim 22, wherein the controlling the air conditioning system further comprises:

calculating an amount of consumable power of an air cooling device of the air conditioning system, after determining the duty of the air heating device as the maximum duty;

determining whether a remaining portion of the surplus regeneration power that has not been consumed by the air heating device is less than the calculated consumable power of the air cooling device; and

controlling the air cooling device to consume all of the remaining portion of the surplus regeneration power, if it is determined that the remaining portion of the surplus regeneration power is less than the consumable power of the air cooling device.

24. The regenerative braking system of claim 23, wherein the consumable power of the air cooling device is calculated based on a current duty of the air cooling device and a rated power of the air cooling device.

25. The regenerative braking system of claim 24, wherein the consumable power of the air cooling device is calculated by multiplying a difference between a maximum duty and the current duty of the air cooling device by the rated power of the air cooling device.

26. The regenerative braking system of claim 23, wherein the controlling the air cooling device comprises:

determining a duty of the air cooling device as a duty in which all of the remaining portion of the surplus regeneration power can be consumed by the air cooling device; and

outputting a driving signal corresponding to the determined duty of the air heating device to the air cooling device.

27. The regenerative braking system of claim 26, wherein the duty of the air cooling device is determined by summing a current duty of the air cooling device and a duty for the air cooling device to consumed the remaining portion of the surplus regeneration power.

28. The regenerative braking system of claim 23, wherein the controlling the air conditioning system further comprises determining a duty of the air cooling device as a maximum duty, if it is determined that the remaining portion of the surplus regeneration power is not less that the calculated consumable power of the air cooling device.